The kicker missed just three field goal attempts during the 2012 season, but has already failed twice this year.
Rosburg told reporters: "After the Cleveland game, I believe I told you at that time that he went back to work, and that's really what he's been doing since then. He hits a lot of kicks in practice.
"He likes to practise, he likes to work on the fine details and fundamentals, and he continues to do that. He's continuing to polish his craft, and I think he recognises the fact that kickers in this league can be successful for a long time if they pay attention to those fine points of detail.
"[Kicking consultant] Randy Brown is coaching him on those things, they're watching tape, they're paying attention to those things, and I fully expect that Justin will continue to improve during the course of his career, because he does that during practice and after."
The Ravens face the Green Bay Packers on Sunday.